If you're new to cycling (and not SuperMan or the Flash), stick with the triple. You'll need it.

Sell the DA shifters for a pretty penny (nice friend!) and buy a replacement shifter. First, though, try stripping down the old one and soaking it overnight in WD-40 to flush out the accumulated gunk. That won't be a permanent repair (there is no permanent repair), but it might buy you a year or so. DO NOT let them talk you out of the triple, at least not yet.

Besides, switching from a triple to a double is not free or even cheap. You'd be spending more $$ than you supposedly save from the "free" shifters.